A big house the seniors rent for the weekendafter prom. Two nights of booze, games, and just plain old fun. Where the boys grill up some burgers & dogs, and the girls chill out in the hot tub. Who wouldn’t wanna go to promhouse?
Sara: “Did you hear there’s a freshmangoing to our promhouse?”
Dan: “Yeah. She’s my date.”
Pretty easily understood. Combination of the words pretty and obvious.
It also a word used by someone who likes to be right all the time and doesn't know the answer to a yes/no question. Combination of probably and obviously.